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Shimizu M, Joyashiki E, Noda H, Watanabe T, Okazaki M, Nagayasu M, Adachi K, Tamura T, Potts JT, Gardella TJ, Kawabe Y. Pharmacodynamic Actions of a Long-Acting PTH Analog (LA-PTH) in Thyroparathyroidectomized (TPTX) Rats and Normal Monkeys. J Bone Miner Res 2016; 31:1405-12. [PMID: 26865415 PMCID: PMC4935665 DOI: 10.1002/jbmr.2811] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 02/05/2016] [Accepted: 02/08/2016] [Indexed: 11/09/2022]
Abstract
Hypoparathyroidism is a disease of chronic hypocalcemia and hyperphosphatemia due to a deficiency of parathyroid hormone (PTH). PTH and analogs of the hormone are of interest as potential therapies. Accordingly, we examined the pharmacological properties of a long-acting PTH analog, [Ala(1,3,12,18,22) , Gln(10) ,Arg(11) ,Trp(14) ,Lys(26) ]-PTH(1-14)/PTHrP(15-36) (LA-PTH) in thyroparathyroidectomized (TPTX) rats, a model of HP, as well as in normal monkeys. In TPTX rats, a single intravenous administration of LA-PTH at a dose of 0.9 nmol/kg increased serum calcium (sCa) and decreased serum phosphate (sPi) to near-normal levels for longer than 48 hours, whereas PTH(1-34) and PTH(1-84), each injected at a dose 80-fold higher than that used for LA-PTH, increased sCa and decreased sPi only modestly and transiently (<6 hours). LA-PTH also exhibited enhanced and prolonged efficacy versus PTH(1-34) and PTH(1-84) for elevating sCa when administered subcutaneously (s.c.) into monkeys. Daily s.c. administration of LA-PTH (1.8 nmol/kg) into TPTX rats for 28 days elevated sCa to near normal levels without causing hypercalciuria or increasing bone resorption markers, a desirable goal in the treatment of hypoparathyroidism. The results are supportive of further study of long-acting PTH analogs as potential therapies for patients with hypoparathyroidism. © 2016 American Society for Bone and Mineral Research.
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Affiliation(s)
- Masaru Shimizu
- Research Division, Chugai Pharmaceutical Co., Ltd., Shizuoka, Japan
| | - Eri Joyashiki
- Research Division, Chugai Pharmaceutical Co., Ltd., Shizuoka, Japan
| | - Hiroshi Noda
- Research Division, Chugai Pharmaceutical Co., Ltd., Shizuoka, Japan
| | - Tomoyuki Watanabe
- Research Division, Chugai Pharmaceutical Co., Ltd., Shizuoka, Japan.,Endocrine Unit, Massachusetts General Hospital, Boston, MA, USA
| | - Makoto Okazaki
- Research Division, Chugai Pharmaceutical Co., Ltd., Shizuoka, Japan
| | - Miho Nagayasu
- Research Division, Chugai Pharmaceutical Co., Ltd., Shizuoka, Japan
| | - Kenji Adachi
- Research Division, Chugai Pharmaceutical Co., Ltd., Shizuoka, Japan
| | - Tatsuya Tamura
- Research Division, Chugai Pharmaceutical Co., Ltd., Shizuoka, Japan
| | - John T Potts
- Endocrine Unit, Massachusetts General Hospital, Boston, MA, USA
| | | | - Yoshiki Kawabe
- Research Division, Chugai Pharmaceutical Co., Ltd., Shizuoka, Japan
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Panaroni C, Fulzele K, Saini V, Chubb R, Pajevic PD, Wu JY. PTH Signaling in Osteoprogenitors Is Essential for B-Lymphocyte Differentiation and Mobilization. J Bone Miner Res 2015; 30:2273-86. [PMID: 26191777 PMCID: PMC5056164 DOI: 10.1002/jbmr.2581] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 06/12/2015] [Accepted: 06/13/2015] [Indexed: 12/18/2022]
Abstract
Cells of the osteoblast lineage provide critical support for B lymphopoiesis in the bone marrow (BM). Parathyroid hormone (PTH) signaling in osteoblastic cells through its receptor (PPR) is an important regulator of hematopoietic stem cells; however, its role in regulation of B lymphopoiesis is not clear. Here we demonstrate that deletion of PPR in osteoprogenitors results in a significant loss of trabecular and cortical bone. PPR signaling in osteoprogenitors, but not in mature osteoblasts or osteocytes, is critical for B-cell precursor differentiation via IL-7 production. Interestingly, despite a severe reduction in B-cell progenitors in BM, mature B-lymphocytes were increased 3.5-fold in the BM of mice lacking PPR in osteoprogenitors. This retention of mature IgD(+) B cells in the BM was associated with increased expression of vascular cell adhesion molecule 1 (VCAM1) by PPR-deficient osteoprogenitors, and treatment with VCAM1 neutralizing antibody increased mobilization of B lymphocytes from mutant BM. Our results demonstrate that PPR signaling in early osteoblasts is necessary for B-cell differentiation via IL-7 secretion and for B-lymphocyte mobilization via VCAM1.
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Affiliation(s)
- Cristina Panaroni
- Division of Endocrinology, Stanford University School of Medicine, Stanford, CA, USA
| | - Keertik Fulzele
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Vaibhav Saini
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Rhiannon Chubb
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Paola Divieti Pajevic
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Joy Y Wu
- Division of Endocrinology, Stanford University School of Medicine, Stanford, CA, USA
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Li X, Garcia J, Lu J, Iriana S, Kalajzic I, Rowe D, Demer LL, Tintut Y. Roles of parathyroid hormone (PTH) receptor and reactive oxygen species in hyperlipidemia-induced PTH resistance in preosteoblasts. J Cell Biochem 2014; 115:179-88. [PMID: 24038594 DOI: 10.1002/jcb.24648] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2013] [Accepted: 08/13/2013] [Indexed: 11/08/2022]
Abstract
Bioactive lipids initiate inflammatory reactions leading to pathogenesis of atherosclerosis. Evidence shows that they also contribute to bone loss by inhibiting parathyroid hormone receptor (PTH1R) expression and differentiation of osteoblasts. We previously demonstrated that bone anabolic effects of PTH(1-34) are blunted in hyperlipidemic mice and that these PTH effects are restored by antioxidants. However, it is not clear which osteoblastic cell developmental stage is targeted by bioactive lipids. To investigate the effects of hyperlipidemia at the cellular level, hyperlipidemic Ldlr(-/-) mice were bred with Col3.6GFPtpz mice, in which preosteoblasts/osteoblasts carry a topaz fluorescent label, and with Col2.3GFPcyan mice, in which more mature osteoblasts/osteocytes carry a cyan fluorescent label. Histological analyses of trabecular bone surfaces in femoral as well as calvarial bones showed that intermittent PTH(1-34) increased fluorescence intensity in WT-Tpz mice, but not in Tpz-Ldlr(-/-) mice. In contrast, PTH(1-34) did not alter fluorescence intensity in femoral cortical envelopes of either WT-Cyan or Ldlr(-/-)-Cyan mice. To test the mechanism of PTH1R downregulation, preosteoblastic MC3T3-E1 cells were treated with bioactive lipids and the antioxidant Trolox. Results showed that inhibitory effects of PTH1R levels by bioactive lipids were rescued by pretreatment with Trolox. The inhibitory effects on expression of PTH1R as well as on PTH-induced osteoblastic genes were mimicked by xanthine/xanthine oxidase, a known generator of reactive oxygen species. These findings suggest an important role of the preosteoblastic development stage as the target and downregulation of PTH receptor expression mediated by intracellular oxidant stress as a mechanism in hyperlipidemia-induced PTH resistance.
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Affiliation(s)
- Xin Li
- Department of Medicine, University of California, Los Angeles, California
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